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Water activity and temperature effects on germination and growth of Eurotium amstelodami , E. chevalieri and E. herbariorum isolates from bakery products
Author(s) -
Abellana M.,
Benedí J.,
Sanchis V.,
Ramos A. J.
Publication year - 1999
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1999.00828.x
Subject(s) - germination , water activity , mycelium , gompertz function , food spoilage , biology , food science , petri dish , horticulture , botany , water content , mathematics , microbiology and biotechnology , genetics , geotechnical engineering , bacteria , engineering , statistics
This study investigated the effect of temperature (5–30 °C), water activity (0·775–0·90 a w ) and their interactions on the temporal rates of germination and mycelial growth of three species of Eurotium on flour wheat sucrose medium. Germination was quite rapid at a w > 0·85, with an almost linear increase with time for all isolates. However, under more extreme water stress, germination was slower. The a w minima for germination were usually lower than those for growth and varied with temperature. The effect of a w × temperature interactions on the lag phases (h) prior to germination and on the germination rates (h −1 ) were predicted using the Gompertz model modified by Zwietering. Eurotium spp. had shown short lag times at 0·90 a w over a wide range of temperatures. At marginal temperatures, lag phases were significantly longer, especially at >15 °C. The temperature × a w profiles for mycelial growth varied between species in terms of rates (mm d −1 ). Predictions of the effect of important environmental factors, such as temperature, a w and their interactions on lag times to germination, germination rates and mycelial growth, are important in the development of hurdle technology approaches to predict fungal spoilage in food products.